E-beam lithography with alignment gating

Abstract

The present disclosure provides one embodiment of a reflective electron-beam (e-beam) lithography system. The reflective e-beam lithography system includes an e-beam source to generate an e-beam; a digital pattern generator (DPG) having a plurality of pixels that are dynamically and individually controllable to reflect the e-beam; a substrate stage designed to secure a substrate and being operable to move the substrate; an e-beam lens module configured to project the e-beam from the DPG to the substrate; and an alignment gate configured between the e-beam source and the DPG, wherein the alignment gate is operable to modulate an intensity of the e-beam.

What is claimed is: 
     
       1. A reflective electron-beam (e-beam) lithography system, comprising:
 an e-beam source to generate an e-beam; 
 a digital pattern generator (DPG) having a plurality of pixels that are dynamically and individually controllable to reflect the e-beam; 
 a substrate stage designed to secure a substrate and being operable to move the substrate; 
 an e-beam lens module configured to project the e-beam from the DPG to the substrate; and 
 an alignment gate configured between the e-beam source and the DPG, wherein the alignment gate is operable to modulate the e-beam to an alternating e-beam with e-beam intensity as a sine function of time. 
 
     
     
       2. The reflective e-beam lithography system of  claim 1 , wherein the alignment gate includes a mechanism to modulate the intensity of the e-beam through an electrical field. 
     
     
       3. The reflective e-beam lithography system of  claim 1 , wherein the alignment gate includes a mechanism with a controllable transmission to modulate the intensity of the e-beam. 
     
     
       4. The reflective e-beam lithography system of  claim 1 , wherein the substrate stage is designed to secure a plurality of substrates configured in a circle. 
     
     
       5. The reflective e-beam lithography system of  claim 1 , wherein
 each of the pixels in the DPG is operable to be in one of on-state and off-state according to a pattern defined in a design layout; and 
 the e-beam modulated by the alignment gate is projected to the plurality of pixels in the DPG simultaneously and is reflected from the DPG as an e-beam array that carries the pattern. 
 
     
     
       6. A reflective electron-beam (e-beam) lithography system, comprising:
 an e-beam source to generate an e-beam; 
 a digital pattern generator (DPG) having a plurality of pixels that are dynamically and individually controllable to reflect the e-beam; 
 a substrate stage designed to secure a substrate and being operable to move the substrate; 
 an e-beam lens module configured to project the e-beam from the DPG to the substrate; and 
 an alignment gate configured between the e-beam source and the DPG, wherein the alignment gate is operable to modulate the e-beam to an alternating e-beam with e-beam intensity changing periodically over time; 
 a clock circuit to generate a clock signal to drive the DPG, wherein 
 the clock signal is a periodic signal of a first frequency; 
 the alternating e-beam by the alignment gate has a periodic intensity of a second frequency; and 
 the first and second frequencies are equal. 
 
     
     
       7. The reflective e-beam lithography system of  claim 6 , further comprising a frequency source to generate an electrical signal of a third frequency, wherein
 the frequency source is coupled with the clock circuit and the alignment gate; and 
 the first and second frequencies equal to the third frequency. 
 
     
     
       8. The reflective e-beam lithography system of  claim 6 , wherein the alignment gate is configured and controlled such that the alternating e-beam is substantially in phase with the clock signal. 
     
     
       9. The reflective e-beam lithography system of  claim 8 , wherein the alternating e-beam is substantially in phase with the clock signal such that minimum intensity nodes of the alternating e-beam are substantially aligned with edges of the clock signal. 
     
     
       10. The e-beam lithography system of  claim 6 , wherein the alignment gate includes a mechanism to modulate the intensity of the e-beam through an electrical field. 
     
     
       11. The e-beam lithography system of  claim 6 , wherein the alignment gate includes a mechanism with a controllable transmission to modulate the intensity of the e-beam. 
     
     
       12. The e-beam lithography system of  claim 6 , wherein the substrate stage is designed to secure a plurality of substrates configured in a circle. 
     
     
       13. The reflective e-beam lithography system of  claim 6 , wherein the e-beam is substantially in phase with the clock signal such that minimum intensity nodes of the e-beam are substantially aligned with edges of the clock signal. 
     
     
       14. An electron-beam (e-beam) lithography system, comprising:
 an e-beam source to generate an e-beam; 
 an alignment gate being operable to modulate an intensity of the e-beam to an alternating e-beam; 
 a digital pattern generator (DPG) having pixels configured in an array to generate an e-beam pattern from the alternating e-beam; 
 a substrate stage designed to secure a substrate and being operable to move the substrate; 
 an e-beam lens module configured to project the e-beam pattern on the substrate; 
 a clock circuit to generate a clock signal to the DPG; and 
 a frequency source coupled to the clock circuit and the alignment gate such that the clock signal and the alternating e-beam are synchronized to have a same frequency. 
 
     
     
       15. The e-beam lithography system of  claim 14 , wherein the alignment gate is configured between the e-beam source and the DPG, and the alignment gate is operable to modulate the intensity of the e-beam so that the modulated intensity changes periodically over time. 
     
     
       16. The e-beam lithography system of  claim 14 , wherein the alignment gate includes a mechanism to modulate the intensity of the e-beam by an electrical field. 
     
     
       17. The e-beam lithography system of  claim 14 , wherein the alignment gate includes a material layer with a controllable transmission to modulate the intensity of the e-beam. 
     
     
       18. The e-beam lithography system of  claim 14 , wherein the frequency source synchronizes the clock circuit and the alignment gate such that minimum intensity nodes of the alternating e-beam are substantially aligned with edges of the clock signal. 
     
     
       19. The e-beam lithography system of  claim 18 , wherein the minimum intensity nodes of the alternating e-beam have intensities substantially zero. 
     
     
       20. The e-beam lithography system of  claim 14 , wherein the pixels in the DPG are operable to have a first subset of the pixels reflecting the alternating e-beam and a second subset of the pixels without reflection.